The action doesn't stay open on the last round .
tried different ammo ,different magazine nothing changed.
Thanks for any help
John

Recoil spring?

Remove the slide and reinsert the slide stop back into the frame. Look into the left hand side of the magazine well. You will see part of the bolt stop protruding into the magazine well. The protruding piece makes contact with the empty magazines follower which rotates the bolt stop up to intercept and lock the slide after the last round has been fired.

Insert an empty magazine and watch to see what the slide stop does. It should immediately swing up into position to catch the slide if one were present. If it doesn't swing up, then you will need to cock the hammer and remove the thumb safety and pull the spring assembly from the little tube that sits along the top of the left grip.

With the spring assembly removed, insert the empty magazine again and watch what happens. If the slide stop now functions correctly, then the problem is with the way the springs detent pin rides on the face of the slide stop. If the slide stop still doesn't lift all the way into position with the insertion of an empty magazine, then the problem likely lies with the little tab on the inside portion of the slide stop that straddles the frame.

With the magazine out, manually work the slide stop up and down and watch how is works and how it rides in the slot. That should provide you with the information you are looking for to identify, or, correct the problem. Good luck!

MALM
Thanks for the help it was the pin that rests on the slide stop was covered with gunk and not letting it move .
Thanks Again
John